This water warmer for brewing formula is perfect for travel, car, and on the go. Built-in 4400mAh large capacity battery for power supply, a real WIRELESS bottle warmer. Before going out, just put the water into the THERMOSTAT. Brewing formula can also be easy. Excellent battery life. At room temperature, 150 ml(5 oz) of water was heated to 104 ℉, it takes about 6 minutes and can be heated about 10 times. 220 ml(7.4 oz) of water heated to 104 ℉, it takes 10 minutes. It can be heated about 5 times. Only in the state of heat preservation, it can be kept warm for 6 hours. It can fully meet your needs of going out. 98 ~ 113℉ adjustable and precise temperature control. Don't need testing temperature over and over again, perfect for brewing formula. The machine is made of food grade plastic( BPA-FREE), not glass. Heating elements are food grade materials. Please do not flush the machine with water directly. Clean the interior with a bottle brush, and wipe the surface with a towel. The bottle and the machine are attached and cannot be disassembled Anti touch design, need to press and hold the power button for 3 seconds to heat, press the power button once to display the battery life.